From 3e43041be68c1288ad9897525a15e21945fb3eb9 Mon Sep 17 00:00:00 2001
From: roconnor-blockstream <roconnor@blockstream.com>
Date: Mon, 27 Mar 2023 09:29:41 -0400
Subject: [PATCH] No need to subtract 1 before doing a right shift

---
 src/int128_struct_impl.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/int128_struct_impl.h b/src/int128_struct_impl.h
index 2eb337cb54..cc17bad167 100644
--- a/src/int128_struct_impl.h
+++ b/src/int128_struct_impl.h
@@ -193,7 +193,7 @@ static SECP256K1_INLINE int secp256k1_i128_check_pow2(const secp256k1_int128 *r,
     VERIFY_CHECK(n < 127);
     VERIFY_CHECK(sign == 1 || sign == -1);
     return n >= 64 ? r->hi == (uint64_t)sign << (n - 64) && r->lo == 0
-                   : r->hi == (uint64_t)((sign - 1) >> 1) && r->lo == (uint64_t)sign << n;
+                   : r->hi == (uint64_t)(sign >> 1) && r->lo == (uint64_t)sign << n;
 }
 
 #endif